Effect of Zr 4+ and Si 4+ substitution on the luminescence properties of CaMoO 4 :Eu 3+ red phosphors

A series of intense red emitting phosphors, Ca0.8-xZrxMo1-xSixO4:0.2Eu 3? (x = 0.025, 0.05, 0.075, 0.1) that could be effectively excited in the UV region was prepared by conventional high temperature solid state reac- tion route. Structural, morphological and photolumines- cence properties of the prepared samples were studied in detail. The incorporation of Zr 4? and Si 4? ions in CaMoO4 lattice maintained the powellite crystal structure. Lumines- cence properties were optimized for 7.5 mol% of Zr 4? and Si 4? concentration. Emission intensities improved more than twice in comparison with CaMoO4:Eu 3? . Life times of the prepared samples improved and the quantum efficiency enhanced to*39 %. The improvement in emission intensity and quantum efficiency is explained in terms of the local distortion around the Eu 3? ions resulting in improved absorption in the UV region. The CIE color co-ordinates of the red emission were in agreement with the values of the standard red phosphors providing potentiality to be used in phosphor converted (pc) white LEDs.